ROLLER CONE BIT

Abstract

A roller cone bit is described. The roller cone bit includes a body having concave sides. Legs are attached or integral to the body. Roller cones are rotatably engaged to the legs. The concave sides are positioned adjacent the legs. A nozzle is positioned in an approximately central portion of the body.

Description

FIELD OF THE INVENTION

The present invention relates to a new and improved roller cone bit.

BACKGROUND OF THE INVENTION

Roller cone bits are used to drill into the earth during mining and drilling operations. Drilling fluids are pumped through the roller cone bit to flush out drill cuttings. The roller cone bits include rollers cones that rotatably connect to the bit via a bearing system. The roller cones rotate as the roller cone bit bores into the earth.

Unfortunately, the design of many existing roller cone bits inadvertently forces drill cuttings into the bearing system of the roller cone bit. When using the roller cone bit, the drilling fluid is shot through flushing nozzles of the roller cone bit, at a high pressure and volume, down to the drilling surface to exhaust the drill cuttings from the bore hole. The flushing nozzles are generally positioned at lateral sides of the bit; however, this combination of the positioning of the flushing nozzles at the lateral sides of the bit and the drilling fluids being sprayed through the nozzles causes the drill cuttings to go into the bearings of the roller cone bits, which causes premature wear on the bit. This premature wear may lead to failure of the roller cone bit.

The design of many existing roller cone bits provides other disadvantages. The flushing nozzles positioned on the lateral sides of roller cone bits often wash away the side walls of the bore hole in soft formations, which makes it next to impossible for the bit to be guided in the direction needed.

In some existing roller cone bits, a center flushing nozzle has been used in the body of the bit. However, the distance between the lateral sides of the body of the bit and the roller cones can create a severe venturi effect, which sucks the drill cuttings in to the roller cones and washes away the metal from around the roller cones of the roller cone bit. This also creates tremendous problems because such bits are injecting drilling fluids under high-pressure and at high-volume, making it very hard for the drill cuttings to get away from the cutting surface of the bore hole, which slows down penetration of the bit and decreases the life of the bit. Further, such drill cuttings cause the bit to fail to have a good course of direction.

SUMMARY OF THE INVENTION

A roller cone bit with a central, extended nozzle and concave sides is described. The roller cone bit provides enhanced flushing of drill cuttings, improved durability, and improved directional control as herein described. The roller cone bit includes an extended nozzle or a tube that extends from a center of a body of the roller cone bit. The extended nozzle or tube is generally centered between cones of the roller cone bit. The nozzle applies a high pressure or a high volume of a drilling fluid depending upon the drilling conditions. The roller cone bit further includes concaved body portions or fluted walls. The concave body portions or fluted walls form gaps or recessed areas to provide for the drill cuttings and drilling fluid to flow past an exterior of the roller cone bit and flush from the bore hole. The concave body portions or fluted walls draw the drill cuttings away from a center of the roller cone bit.

In a first aspect, a roller cone bit is described. The roller cone bit includes a body having concave sides. Legs are attached or integral to the body with roller cones rotatably engaged with the legs. The concave sides are positioned adjacent the legs. A nozzle is positioned in an approximately central portion of the body. The nozzle includes an extending portion and an opening, and the opening is positioned a distance from a surface of the body.

In another aspect, a method of drilling into a rock or earth formation is described. The method includes providing a roller cone bit including a body having concave sides, legs attached or integral to the body, roller cones rotatably engaged to the legs, the concave sides positioned adjacent the legs, and a nozzle. The nozzle includes an extending portion and an opening. The nozzle is positioned in an approximately central portion of the body, and the opening is positioned a distance from a surface of the body. The method includes connecting the roller cone bit to a drill string and rotating the roller cone bit. The method includes directing fluid to the nozzle and flushing drill cuttings with the fluid past the concave sides.

In another aspect, a roller cone bit is described. The roller cone bit includes a body having concave sides. Legs are attached or integral to the body. Roller cones are rotatably engaged to the legs. The concave sides are positioned adjacent the legs to provide flushing of drill cuttings from a borehole. The roller cone bit includes a nozzle to spray a drilling fluid. The nozzle includes an extending portion and an opening. The nozzle is positioned in an approximately central portion of the body. The opening is positioned a distance from a surface of the body.

In another aspect, a roller cone bit to drill into earth or rock is described. The roller cone bit includes a body. The body includes an upper portion and a lower portion. The upper portion includes a threaded connection portion to connect with a drill string to rotate the roller cone bit. Three legs are attached or integral to a perimeter of the body. Each of the legs has an end at the lower portion of the body. A roller cone is rotatably engaged to the ends of each of the legs via a bearing system. Each of roller cones includes an inner cutter, a center cutter, and an outer cutter. The body has three concave sides extending from the upper portion to the lower portion. The concave sides are positioned between the legs. The concave sides form gaps to flush drill cuttings. A nozzle extends from the lower portion of the body to spray a drilling fluid. The nozzle includes an extending portion and an opening. The nozzle is positioned in an approximately central portion of the lower portion of the body. The nozzle extends to a point approximately clearing the center cutter of the roller cone bit. The nozzle is in fluidic communication with a fluid line of the body.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a first perspective view of the roller cone bit.

FIG. 2 is a second perspective view of the roller cone bit.

FIG. 3 is a top view of the roller cone bit.

FIG. 4 is a sectional view of the roller cone bit.

FIG. 5A shows a threading engagement between the nozzle and the body of the roller cone bit.

FIG. 5B shows a binding taper engagement between the nozzle and the body of the roller cone bit.

FIG. 5C shows a fix welded engagement between the nozzle and the body of the roller cone bit.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A roller cone bit will now be described with reference to the figures. The roller cone bit includes a nozzle that extends from a center of a body of the roller cone bit. The roller cone bit further includes concaved sides between legs of the body of the roller cone bit. The nozzle and concaved sides improve flushing of drill cuttings from the bore hole by directing the drill cuttings away from a center of the roller cone bit. The drill cuttings flush to the concave sides, which typically provide an unobstructed path for the drill cuttings to exit the bore hole.

A roller cone bit 10 is shown in FIG. 1. The roller cone bit 10 is attached to a drill string of a drilling rig. The roller cone bit 10 includes a plurality of cones 100 that are used for drilling or cutting into rock or earth. The cones 100 rotate to cut and grind the earth or rock formation, as the drill string is rotated and urged downward by the drilling rig.

As shown in FIG. 1, the roller cone bit 10 includes a cone 100a, a cone 100b, and a cone 100c. As shown in FIG. 3, each of the cones 100a-c include an inner cutter 110, a center cutter 120, and an outer cutter 130 that form a cutting surface for the cones 100a-c. Each of the cones 100a-c are generally an integral structure. The cones 100a-c vary in diameter from approximately one inch to approximately 8 inches. The center of the cones 100a-c will generally have an approximately zero diameter. The inner cutter 110 is generally smaller in size or diameter as compared to the center cutter 120, and the center cutter 120 is generally smaller in size or diameter as compared to the outer cutter 130. The cutters 110, 120, and 130 include one or more protrusions 135 that cut into the earth or rock. Typically, a plurality of the protrusions 135 are positioned about the periphery or exterior of the cutters 110, 120, and 130. The protrusions 135 may include a combination of different sized and shaped teeth, nubs, or other cutting structures.

With reference to FIG. 1, the cones 100a-c form a groove 133 between the outer cutter 130 and the center cutter 120 and a groove 123 between the center cutter 120 and the inner cutter 110. These grooves 123 and 133 allow the protrusions 135 of one of the rotating cones 100a-c to clear the adjacent rotating cone 100a-c, as the protrusions 135 may enter the grooves 123 and 133 of the adjacent cones 100a-c during the rotation of the cones 100a-c. Further, for each cone 100a-c, the protrusions 135 are typically positioned offset from the protrusions 135 on the adjacent cone 100a-c. This allows the protrusions 135 on the cones 100a-c to interweave or mesh with the protrusions 135 on the adjacent cones 100a-c. This reduces open space between the rotating cones 100a-c and the protrusions 135 and provides the protrusions 135 with maximum surface contact in the drilling face.

The roller cone bit 10 includes a body 200. The body 200 has a generally cylindrical shape forming an exterior surface 225. The cones 100a-c are positioned on one end of the body 200 The roller cone bit 10 further includes a threaded connecting portion 400 to connect with the remainder of the drilling string. The threaded connecting portion 400 is formed on the opposite end of the body 200 from the cones 100a-c.

The body 200 includes a plurality of legs 150 that are attached or integral with the body 200. The roller cone bit 10 of FIGS. 1-3 includes three legs 150. As shown in FIG. 1, the body 200 includes a leg 150a, a leg 150b, and a leg 150c.

Each of the legs 150a-c includes an end 160a-c that rotatably connects to the cones 100a-c by a bearing system 140. The bearing system 140 may include an open bearing engagement or a sealed bearing engagement. The bearing system 140 provides for the rotation of the cones 100a-c relative to the ends 160a-c. The cones 100a-c are rotatably connected to the roller cone bit 10 via the bearing system 140. The ends 160a-c may form or include an axis, axle, or pin that engages an interior or a back surface of the cones 100a-c. Bearings are positioned about the axis, axle, or pin. The back surface of the cones 100a-c may include an open portion to receive the axis, axle, or pin in a bearing engagement.

The legs 150 are circumferentially spaced around the exterior of the body 200. Generally, the legs 150 are spaced evenly around the exterior of the body 200. The legs 150a-c are next to or integral with concave sides 210 in a perimeter 205 of the body 200. One of the concave sides 210 is positioned between each of the legs 150a-c. Generally, the concave sides 210 are also spaced evenly around the exterior of the body 200. The concave sides 210 form flutes on the exterior surface 225 of the body 200. A recessed area 215 is formed by the concave side 210. The concave sides 210 and the recessed areas 215 provide for drill cuttings to pass or flush past the roller cone bit 10. This reduces wear on the cones 100a-c and the bearing system 140, and also improves directional control of the bit 10.

The concave side 210 may include a curving cut-out, scooped, a curved space, or a curved recess between the legs 150a-c. The concave sides 210 may have an arc of approximately 60-70 degrees. Depending upon the application and drilling condition, the concave sides 210 may have arcs of approximately 30-60 degrees or approximately 70-100 degrees.

The concave sides 210 generally extend from an upper portion 203 of the body 200 to a lower portion 207 of the body 200. The concave sides 210 generally extend the length of the body 200. A length Y (shown in FIG. 1) of the concave sides 210 is generally parallel to an axis of rotation of the roller cone bit 10. The concave sides 210 may have a depth into the body 200 of approximately ¼ inch to approximately 2 inches.

The concave sides 210, between the legs 150a-c, where flushing nozzles are typically located in convention roller cone bits, increases the life of the roller cone bit 10 and its rate of penetration into the rock or earth substrate. The concave sides 210 provide for the drill cuttings cut from the bore hole to pass through or by the recessed areas 215 in the body 200 of the roller cone bit 10 and away from the bearing system 140 of the roller cones 100. The concave sides 210 improve penetration rate because there is less chance to regrind the drill cuttings because the drill cuttings have an easier path of little resistance to follow in order to clear the cutting surface.

The roller cone bit 10 may be formed from steel and other alloys commonly used in drilling and mining operations. The roller cone bit 10 may be manufactured using conventional manufacturing techniques, such as milling and welding, commonly used for roller cone bits. The legs 150s may be forged or cast and welded together after the roller cones 100a-c are attached to the bearing system 140. The desired thread may then be machined on the back of the roller cone bit 10 to form the threaded connecting portion 400. The roller cone bit 10 may also be manufactured by modifying existing roller cone bits, i.e., removing exterior nozzles to create the desired concave surfaces and drilling the center port to receive the nozzle.

In alternative embodiments, then body 200 may include fewer or additional legs 150 and concave sides around its periphery. For example, the body 200 may include five legs 150 with a concave side 210 in between each of the five legs 150. For example, the body 200 may include two legs 150 with concave sides 210 between each of the two legs 150.

With reference to FIG. 3, the roller cone bit 10 includes a nozzle 300. The nozzle 300 extends from a center portion surface 310 of a center portion 230 of the body 200. The nozzle 300 is centered between the cones 100a-c. The nozzle 300 includes a nozzle or tube-like extension 320. The nozzle 300 includes a nozzle opening 330. The nozzle opening 330 disperses or sprays the drilling fluid. The nozzle 300 is in fluidic communication via lines or conduits through the roller cone bit 10 and the drill string to receive the drilling fluids. A cross sectional view of the roller cone bit 10 is shown in FIG. 4. The drilling fluid passes through an interior 405 of the body 200 that is in fluidic communication with a lower opening 332 of the nozzle 300. The drilling fluid is forced through the nozzle 300 and discharged at the nozzle opening 330. With reference to FIG. 1, the nozzle extension 320 extends from the center portion surface 310 to just clear or just extend past the center cutter 120 of the cones 100a-c.

The nozzle 300 applies a high-pressure or a high volume of drilling fluid depending on the requirements for a specific drilling condition. This is accomplished by changing the nozzle 300. For example, a first nozzle 300 with a first diameter may be replaced by a second nozzle 300 with a second diameter. The larger the diameter of the nozzle opening 330, then the more volume of drilling fluid will be supplied to the bore hole. Likewise, the smaller the diameter of the nozzle opening 330, then the more pressure the drilling fluid will be supplied with into the bore hole. The nozzle opening 330 may have a diameter of approximately 1/16 inch to approximately ¾ inch, depending upon the requirements of the drilling conditions.

The nozzle 330, with the smaller diameter, is useful when used in the horizontal directional operations in which drilling conditions may change rapidly from hard surfaces to soft surfaces. The nozzle 300, with the smaller diameter, creates the higher pressure jetting action of the drilling fluid, which washes a pilot hole in advance of the roller cone bit 10 in the soft formations to allow the roller cone bit 10 to follow the direction created by the pilot hole. As the nozzle 300 is in the center portion 230, the nozzle 300 is not washing away the sidewalls of the bore hole. This helps to maintain directional control of the roller cone bit 10. The high-pressure jetting action also forces all drill cuttings from the center of the roller cone bit 10 to an exterior of the bit 10, which helps to protect the bearing system 140 of the bit 10. This helps to keep the drill face cleaner for a rapid penetration, as the roller cone bit 10 is not regrinding drill cuttings.

The roller cone bit 10 further includes the concave sides 210. This concaving of the body 200 between the legs 150a-c, where flushing nozzles are typically located, increases the life of the roller cone bit 10 and its rate of penetration into the rock or earth substrate. The concave sides 210 provide for the drill cuttings to pass through or by the recessed areas 215 in the body 200 of the roller cone bit 10 and away from the bearing system 140 of the roller cones 100a-c. The concave sides 210 improve penetration rate because there is less chance to regrind the drill cuttings because the drill cuttings have an easier path of little resistance to follow in order to clear the cutting surface. The flushing from the center of the roller cone bit 10 out and up through the concave sides 210 performs a venturi effect to help suck the drill cuttings away from the roller cones 100a-c, while the roller cone bit 10 is drilling for maximum flushing.

The roller cone bit 10 will now be described with reference to the following examples. A typical 5½ inch roller cone bit 10 may use the nozzle 300 with a diameter of approximately ⅛^th inch for a horizontal directional drilling operation. This nozzle 300 provides high pressure flow of the drilling fluid to blow away dirt in the soft formation to make a pilot hole in the soft formation for the roller cone bit 10 to follow. The nozzle diameter of ⅛^th inch still provides sufficient volume of drilling fluid for the drilling of harder formations, which does not remove as much drill cuttings, since the drilling speed is reduced. The same roller cone bit 10 may be used in a mining operation such as for coal or copper, and use a nozzle 300 with an approximately ⅜^th inch diameter opening. This ⅜^th inch diameter opening provides a higher volume of drill fluids to remove cuttings from the mining operation.

The roller cone bit 10 may have a fixed or changeable nozzle 300. The nozzle 300 is in fluidic communication with the interior 405 of the body 200 to receive the drilling fluid from the interior 405 of the body 200. The nozzle 300 includes the lower opening 332 to receive the drilling fluid from the interior 405, and the nozzle 300 includes the nozzle opening 330 to discharge the fluid. The nozzle 300 may pass through the center portion surface 310 and into the interior 405 of the body 200 to fluidly connect with the interior 405 to receive the drilling fluid. The drilling fluid is pumped through the drill string, to the interior 405, and out the nozzle 300.

The nozzle 300 may threadably connect to the center portion surface 310 of the body 200 to provide a changeable nozzle. For example, as shown in FIG. 5A, a lower portion 325 of the nozzle 300 may include a threaded engagement surface 327 that engages an opening 312 in the center portion surface 310. This nozzle 300 of FIG. 5A may be removed and exchanged with a different nozzle 300 depending upon the drilling conditions. For example, the nozzle 300 with a first, smaller diameter may be unthreaded from the opening 312 and replaced with another nozzle 300 with a second, larger diameter. In other aspects, the nozzle 300 may be in a fixed engagement with the lower portion 325 of the nozzle 300 engaged to the opening 312 or to the center portion surface 310 via a variety of mechanical fastening techniques. For, example, as shown in FIG. 5B, the lower portion 325 of the nozzle 300 may form a binding taper to engage with the opening 312. Further, as shown in FIG. 5C, the lower portion 325 of the nozzle 300 may be welded to the opening 312 in a fixed engagement. In other aspects, the nozzle 300 may connect at the center portion surface 310 and receive fluid passing through the opening 312 of the center portion surface 310, with the opening 312 forming a passage or conduit to fluidly connect with the interior 405.

With reference to FIG. 1, the nozzle 300 extends to a point just clearing the center cutter 120 on the roller cone bit 10. The length of the nozzle 300 may be brought back to approximately one inch from clearing the center cutter 120 in the roller cone bit 10. As the length of the nozzle 300 decreases, the risk of causing venturi effect increases, which will create a sand-blasting effect by the drilling fluid that washes away the steel from the cutters 110, 120, and 130 on the cones 100a-c. This may result in failure of the bit 10. The actual length of the nozzle 300 will vary depending upon the size and diameter of the roller cone bit. For example, on a roller cone bit 10 with a 6½ inch diameter, the nozzle will have a length of approximately 2½ inches.

The roller cone bit 10 with the nozzle 300 allows for the drill cuttings to have free passage up and through the concave sides 210 between the legs 150a-c. This encourages the drill cuttings to move from the center to the perimeter 205 of the body 200 and away from the cones 100. This provides for more efficient flushing and removal of the drill cuttings by the drilling fluid.

With reference to FIGS. 1 and 3, the roller cone bit 10 includes three legs 150a-c and three concave sides 210. The roller cone bit 10 includes the three concave sides 210 arranged at approximately 120 degree intervals about the perimeter 205 of the roller cone bit 10. The legs 150a-c and the three concave sides 210 are alternatingly arranged about the perimeter 205 of the roller cone bit 10. Said another way, there is one of the concave sides 210 between each pair of the legs 150a-c. This provides three passages or pathways for the drilling fluid to flush away the drill cutting from the bore hole. Importantly, this directs the drill cuttings away from the roller cones 100a-c and the bearing system 140.

The roller cone bit 10 includes the nozzle 300 centered in its body 200. The nozzle 300 is a tubular member formed from steel and other alloys commonly used in drilling and mining operations. The roller cone bit 10 does not have nozzles around its perimeter 205.

It should be understood from the foregoing that, while particular embodiments of the invention have been illustrated and described, various modifications can be made thereto without departing from the spirit and scope of the present invention. Therefore, it is not intended that the invention be limited by the specification; instead, the scope of the present invention is intended to be limited only by the appended claims.

Claims

1. A roller cone bit, comprising:

a body having concave sides; and,

a nozzle to spray a drilling fluid, the nozzle comprising an extending portion and an opening, wherein the nozzle is positioned in an approximately central portion of the body.

2. The roller cone bit according to claim 1, wherein legs are integrally attached to the body, and roller cones are rotatably engaged to the legs.

3. The roller cone bit according to claim 2, wherein the concave sides are positioned adjacent to the legs to provide flushing of drill cuttings from a borehole.

4. The roller cone bit according to claim 1, wherein the opening of the nozzle is positioned a distance from a surface of the body.

5. The roller cone bit according to claim 2, wherein the legs and the concave sides are alternatingly arranged about a perimeter of the roller cone bit.

6. The roller cone bit according to claim 2, wherein one of the concave sides is positioned between a pair of the legs.

7. The roller cone bit according to claim 2, wherein the nozzle extends to a point approximately clearing a center cutter of the roller cone bit.

8. The roller cone bit according to claim 4, wherein the extending portion of the nozzle extends from a surface of the central portion of the body, and the opening is positioned away from the surface of the central portion of the body.

9. The roller cone bit according to claim 1, wherein the concave sides extend from an upper portion of the body to a lower portion of the body.

10. The roller cone bit according to claim 1, wherein a length of the concave sides is generally parallel to an axis of rotation of the roller cone bit.

11. The roller cone bit according to claim 1, wherein the bit comprises a first nozzle with a first opening having a first diameter, wherein the bit comprises a second nozzle with a second opening having a second diameter, wherein the second diameter is larger than the first diameter, the second nozzle provides a greater volume of drilling fluid, and the first nozzle provides the drilling fluid at a greater pressure.

12. The roller cone bit according to claim 1, wherein the nozzle is removably engaged to the body.

13. The roller cone bit according to claim 1, wherein the nozzle is in fluidic communication with an interior of the body, and a drilling fluid is forced through the interior of the body and into the nozzle.

14. The roller cone bit according to claim 1, wherein the nozzle passes through a center portion surface of the body, a lower opening of the nozzle is in fluidic communication with an interior of the body, and a drilling fluid is forced through the interior of body and into the lower opening, and the drilling fluid is forced through the extending portion of the nozzle and is discharged at the nozzle opening.

15. A roller cone bit, comprising:

a body having concave sides, an upper portion, and a lower portion;

legs are integrally attached to the body, and roller cones are rotatably engaged to the legs;

the concave sides are positioned around an exterior of the body, the concave sides extend from the upper portion of the body to the lower portion of the body, and the concave sides form gaps in the exterior of the body to provide passage of drill cuttings past the body; and,

at least one of the concave sides is positioned between a pair of the legs.

16. A method of drilling into a rock or earth formation, comprising:

providing a roller cone bit, comprising: a body having concave sides; legs integrally attached to the body; roller cones rotatably engaged to the legs; the concave sides positioned adjacent the legs; and, a nozzle, comprising an extending portion and an opening; wherein the nozzle is positioned in an approximately central portion of the body; wherein the opening is positioned a distance from a surface of the body;

connecting the roller cone bit to a drill string;

rotating the roller cone bit;

directing fluid to the nozzle; and,

flushing drill cuttings with the fluid past the concave sides.

17. The method according to claim 16, further comprising directing drill cuttings away from the roller cones.

18. The method according to claim 16, further comprising making a pilot hole in the rock or earth formation with the drilling fluid from the nozzle.

19. The method according to claim 16, further comprising adjusting an opening size of the nozzle to modulate pressure and volume of the drilling fluid.

20. A roller cone bit, comprising:

a body having concave sides;

legs integrally attached to the body;

roller cones rotatably engaged to the legs;

the concave sides positioned adjacent the legs to provide flushing of drill cuttings from a borehole; and,

a nozzle to spray a drilling fluid, comprising an extending portion and an opening;

wherein the nozzle is positioned in an approximately central portion of the body;

and, wherein the opening is positioned a distance from a surface of the body.

21. A roller cone bit to drill into earth or rock, comprising:

a body, the body including an upper portion and a lower portion, the upper portion including a threaded connection portion to connect with a drill string to rotate the roller cone bit;

three legs engaged to a perimeter of the body, each of the legs having an end at the lower portion of the body;

a roller cone rotatably engaged to the ends of each of the legs via a bearing system, wherein each of roller cones includes an inner cutter, a center cutter, and an outer cutter;

the body having three concave sides extending from the upper portion to the lower portion, the concave sides positioned between the legs, the concave sides forming gaps to flush drill cuttings; and,

a nozzle extending from the lower portion of the body to spray a drilling fluid; the nozzle comprising an extending portion and an opening; wherein the nozzle is positioned in an approximately central portion of the lower portion of the body; wherein the nozzle extends to a point approximately clearing the center cutter of the roller cone bit; and, wherein the nozzle is in fluidic communication with a fluid line or an interior of the body.